The invention relates to a bus subscriber for a bus system, a bus system for a motor vehicle and a method for allocating addresses in a bus system.
Bus subscribers for a bus system, bus systems and methods for allocating addresses in a bus system are sufficiently well known from mass production for motor vehicles and from the general related art, for example. Such a bus system is used for data transmission between a plurality of bus subscribers via a common transmission path where the subscribers are not involved in the data transmission between other subscribers.
Bus systems are used particularly in motor vehicles for connecting individual electronic bus subscribers in the form of controllers, which actuate respective control elements in the motor vehicle, for example. So that the bus subscribers are able to interchange data with one another and hence to communicate with one another, they are connected to one another by at least one line element, for example.
Such a line element may comprise one or more metal wires that are sheathed with a sleeve particularly composed of plastic. Signals and hence data, which are also called messages, to be transmitted between the bus subscribers are forwarded by voltage differences and encrypted or decrypted by a protocol, for example. In order to ensure error-free communication, the bus subscribers on the bus system require a respective explicit address, so that each bus subscriber can be explicitly identified. The allocation of the addresses for the bus subscribers is also called coding. For automatic address allocation, there is the possibility of isolating the bus system at each bus subscriber, for example, and forwarding messages, i.e. the signals, only conditionally or performing electrical measurements. This results in a high level of cabling complexity and also in high susceptibility to error. Alternatively, a separate wire can be used and laid for performing the address allocation. The general related art also discloses methods in which additional contacts of a connector for the bus subscribers are used differently or passive components are installed in the connector.
DE 101 23 802 B4 reveals it to be known practice to provide such coding by EEPROM or by connector codings, for example. Furthermore, DE 101 23 802 B4 reveals a control system for controlling electronically actuatable motor vehicle components to be known. The control system comprises a single-wire bus system with at least one super ordinate control device with at least two further subscribers that are each associated with at least one motor vehicle component. In this case, the super ordinate control device and the further subscribers are connected to one another via a bus that comprises at least two data lines. At least one switching apparatus is provided that is controlled by the super ordinate control unit and that can specifically either disconnect or connect each of the at least two further subscribers individually.
EP 1 139 609 A2 discloses a bus system with a plurality of bus subscribers, wherein each bus subscriber is connected to at least two connecting lines. In this case, provision is made for each bus subscriber to have an associated electronic circuit portion. The circuit portion can be connected to the connecting lines in different connection combinations. The connection portion recognizes the respective connection combination of the connected connecting lines and codes the bus subscriber on the basis of the recognized connection combination.
US 2005/015474 A1 discloses a sensor element for a bus system in a motor vehicle. The sensor element has a first number of contact connections that can be used to connect the sensor element to the bus lines of the bus system, which have different potentials. In this case, provision is made for the first number to be greater than the number of bus lines. In addition, a first device is provided that measures and evaluates the potential at at least one of the contact connections. Furthermore, a second device is provided that allocates a specific address coding to the sensor element from the measured and evaluated potential.
US 2003/0201882 A1 reveals an addressable monitoring system to be known. The monitoring system comprises a plurality of sensors. Each of the sensors can be connected to a wiring harness that comprises four lines. Contacts can be used to connect the respective sensor to the lines. Depending on the connection state of two of these contacts, the respective sensor can determine it own address.
Finally, U.S. Pat. No. 4,538,262 discloses a bus subscriber with contacts that can be used to connect the bus subscribers to lines of a bus system. An address for the bus subscriber can be allocated on the basis of a respective connection state of the contacts with respect to the lines.
DE 103 54 602 A1 reveals a bus system for a motor vehicle to be known that has at least two bus subscribers. The bus system has at least one data line as a first line, at least one power supply line as a second line and at least one ground line as a third line. The bus subscribers also each have at least one connection element that comprises at least two contacts. The contacts can each be connected to one of the lines.
A first of the contacts is a voltage connection that can be connected to the power supply line. The second contact is a data communication connection that can be connected to the data line. The respective connection element also comprises a third contact, which is a ground connection and can be connected to the ground line. Furthermore, a fourth contact of the respective connection element is provided, which is a configuration connection.
The configuration connection is used for the address allocation of the bus subscriber, that is to say for coding. In this case, the configuration connection may be connected to the power supply line or to the data line or to the ground line or open, so that four states and hence four address options are provided. The provision of this additional configuration connection results in a relatively high level of cabling complexity for the bus subscriber and hence for the bus system.